摘要:
Silicon nitride base sintered body consists of: 1 to 20 wt % (as oxides) of at least one of rare earth elements; 0.5 to 8 wt % of V (as V.sub.2 O.sub.5); 0.5 to 8 wt % (as oxides) of at least one of Nb, Ta, Cr, Mo and W; sum of the Va and VIa group elements according to the Periodic Table of the International Version (as oxides) being 1 to 10 wt %; and balance silicon nitride. It has high strength of 690-880 MPa (70-90 kgf/mm.sup.2) and high oxidation resistance both at 1350.degree. C. It is produced by 2 stage gas-pressure sintering in pressurized N.sub.2 atmosphere, primarily at 1700.degree.-1900.degree. C. at 1 MPa (10 atm) or less and secondarily at 1600.degree.-1900 C. at 10 MPa (100 atm) or above.
摘要:
A triphenol type compound represented by the following formula: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.6 independently represent hydrogen, a halogen, a C.sub.1 -C.sub.5 alkyl group or a C.sub.1 -C.sub.5 alkoxy group.The triphenol type compound can be used, as a branching agent, for the production of a polycarbonate comprising (A) a carbonic acid component unit, (B) a divalent phenol component unit, and (C) a triphenol type compound component unit derived from the above-mentioned triphenol type compound. The triphenol type compound unit (C) is used in an amount of 0.01 to 10 mole %, based on the divalent phenol component unit (B) and the intrinsic viscosity [.eta.], determined at 25.degree. C. in methylene chloride, of the polycarbonate is 0.4 to 1.0 dl/g and the glass transition temperature (Tg), determined by a differential scanning type calorimeter is 150.degree. C. to 300.degree. C.
摘要:
A triphenol type compound represented by the following formula: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.6 independently represent hydrogen, a halogen, a C.sub.1 -C.sub.5 alkyl group or a C.sub.1 -C.sub.5 alkoxy group.The triphenol type compound can be used, as a branching agent for the production of a polycarbonate comprising (A) a carbonic acid component unit, (B) a divalent phenol component unit, and (C) a tripenol type compound component unit derived from the above-mentioned triphenol type compound. The triphenol type compound unit (C) is used in an amount of 0.01 to 10 mole %, based on the divalent phenol component unit (B) and the intrinsic viscosity [.eta.], determined at 25.degree. C. in methylene chloride, of the polycarbonate is 0.4 to 1.0 dl/g and the glass transition temperature (Tg), determined by a differential scanning type calorimeter is 150.degree. C. to 300.degree. C.
摘要:
Disclosed is a process for the preparation of phenols which comprises reacting an .alpha.-hydroxyalkyl-substituted aromatic compound and/or an .alpha.,.beta.-unsaturated alkyl-substituted aromatic compound with hydrogen peroxide in the presence of an acid catalyst, in which hydrogen peroxide is diluted with a diluent, especially acetone, so that the volume is at least 10 times the original volume, and the diluted hydrogen peroxide is supplied in a divided manner to at least two portions of a reaction vessel or the diluted hydrogen peroxide is scattered by sprinkling into the reaction vessel. According to a preferred embodiment, the diluted hydrogen peroxide is continuously supplied to the gas phase in the reaction vessel from a scattering device which is similar to but separate from a scattering device for supplying the starting aromatic compound, particularly, a product formed by oxidizing an isopropyl aromatic compound with molecular oxygen.According to this process, the efficiency of utilization of hydrogen peroxide is increased and a phenol of high quality can be obtained in a high yield with a high safety.
摘要:
A process for the preparation of peroxides by condensation reaction of a tertiary organic hydroperoxide with a tertiary alcohol, which is characterized in that zinc chloride is present as a catalyst in an amount of at least 1% by weight based on the tertiary alcohol, is disclosed. This process can be advantageously applied to continuous manufacture of peroxides, and according to this process, peroxides can be obtained in high yields.
摘要:
A laminated capacitor has an end surface pitch Pe, which defines an interval between adjacent first and second external terminal electrodes disposed on end surfaces having shorter sides in a body of a laminated capacitor, which is equal to or less than about 0.9 times of a side-surface pitch Ps, which defines an interval between adjacent first and second external terminal electrodes disposed on side surfaces having longer sides, in order to enhance the effect of magnetic-flux cancellation at the end surfaces and to reduce the equivalent series inductance of the whole laminated capacitor.
摘要:
A sintered body of silicon nitride with high density, strength, toughness, and hardness, which can be used for a structural part of an engine, etc. The sintered body of the invention includes 80 to 94 wt % Si.sub.3 N.sub.4, 2 to 10 wt % Mg compound calculated in MgO equivlent, and 2 to 10 wt % Y compound calculated in Y.sub.2 O.sub.3 equivalent. The Si.sub.3 N.sub.4 contains 5 to 40% .alpha.-phase. The sintered body is manufactured in the following steps: (a) mixing powdery Si.sub.3 N.sub.4 with a Mg compound and a Y compound in the above proportions, and then molding the mixture in which the Si.sub.3 N.sub.4 powder contains 80% or more .alpha.-phase and its grains are 1 .mu.m or less in diameter on average; (b) performing primary sintering at 1,600.degree. C. or less in an atmospher of nitrogen or of an inert gas at 20 atm or less; and (c) performing secondary sintering at 1,400.degree. to 1,600.degree. C. in an atmosphere of nitrogen or of an inert gas at 300 atm or more.
摘要翻译:具有高密度,强度,韧性和硬度的氮化硅烧结体,其可用于发动机的结构部件等。本发明的烧结体包含80〜94重量%的Si 3 N 4,2〜10重量% 镁化合物按MgO计算,和2〜10重量%的Y化合物按Y2O3当量计算。 Si3N4含有5〜40%的α-相。 该烧结体按以下步骤制造:(a)以上述比例混合粉末状Si 3 N 4与Mg化合物和Y化合物,然后将其中Si 3 N 4粉末含有80%以上的α-相及其晶粒的混合物 平均直径1米以下; (b)在大气压的氮气或20atm以下的惰性气体中,在1600℃以下进行初次烧结; 和(c)在氮气气氛中或在大气压为300atm以上的惰性气体中,在1400℃〜1600℃进行二次烧结。
摘要:
Disclosed is a heat-resistant flame-retardant epoxy resin composition comprising a halogen-containing epoxy resin obtained by reacting a trifunctional epoxy compound having a specific structure with a halogenated bisphenol in the presence of a catalyst. Furthermore, a novel specific trifunctional epoxy compound is disclosed, which is valuably used for the production of the above-mentioned halogen-containing epoxy resin.
摘要:
A plurality of ceramic green sheets each provided with electrodes are prepared and laminated to form a laminated unit. The laminated unit is then vacuum packed in a rubber covering or a synthetic resin sheet. The vacuum packed laminated unit is pressed by hydrostatic pressure within a high-pressure vessel, whereby the plurality of ceramic green sheets are pressed to form a single ceramic sheet, which is then baked to form a chip.
摘要:
A liquid peroxide composition comprising dicumyl peroxide and a dicumyl peroxide derivative having one nucleus substituted by an alkyl group having 1 to 3 carbon atoms is disclosed. This peroxide composition can easily be handled because it is liquid, and it is very valuable as a cross-linking agent for an olefin polymer or a synthetic rubber.